Retrievable bridge plug and pack-off



United States Patent 1111 3,542,128

[72] Inventor Arthur L. Owen 3,107,725 10/1963 Flickinger 166/187 Houston, Texas 3,244,233 4/1966 Villalon 166/1'23 [2n P "A120 Primary ExaminerJamesA.Leppink [22] Wed Anoniey-CarlosA Torres [45] Patented Nov. 24,1970 [73] Assignee Electric Wireline Specialties, Inc.

5" ABSTRACT: A tool having a tubular central mandrel movable a corporation. of Texas axially through an outer body which includes a cone spreader, I expandable metal anchoring fingers, a locking mechanism and an elastomeric packer. Shear pins extend through the mandrel [54] r gg "i AND PACKOFF and sever in sequence when the mandrel is moved upwardly 1 through the body by a setting mechanism to slide the cone [52] US. Cl. 166/123, under the fingers and compress the packer which sequentially 166/182; 166/187 7 expands the fingers and packer to anchor-the tool and seal it [51] lnt.Cl.... EZlb 23/00, against a surrounding well conduit. The last pin to sever I F21! 33/12 releases the tool from the setting mechanism and the locking [50] Field of Search 166/123, mechanismengages the mandrel to lockthe tool in place. The a 181, 182, 187 tool is released by pulling upwardly on' the locking mechanism which first releases the packer and'subsequently releases the m (med I locking fingers to prevent'the tool from being blown uphole by UNITED STATES PATENTS differential well pressure. The end of themandrel may be 2,718,926 9/1955 Schlegel 1' 166/182 Plugged p and, a second Pee may be p y to 3,100,533 8/1963 Fredd 166/1 81 P me 27 Ila L a I Sb 150 h -15 v i I 15b '15 r a I 75c J 1s m l3 "d 13o f Y q r y m s diis n wa sbf h at r m st t ns numerous, bulky-components are'ernployed'in the eon tion of such toolrthe internal; dimensions:are of necessity.

slips arid one .orimo P s v n on l tes enera ly. t e ie ofwell through the mandrel leftiopenfand conyersion to-a plug is eftreatrnent and operation. More specifically; the pr'ese ntinvention relates to a new and imprpved retrieyablebridge plug and 'ectionof a well casing, liner or other well conduit at'a subsurface localpack-offqfor completely sealing or for packing-off tion. I i 2. Descriptionofthe'BriorArt Thepriorart discloses a variety of toolsdesigned to seal or anchor to a well conduit at a sub'snrfaceldca while in other instances, 'it mayjbe'neees'saryvto sealoff a leaki ing, dam:aged,' or perforated section ofvthe conduit without in-some" instances,'a complete plug of the well fc onclpi is requireddisrupting fluid flow past the sealed in sectionJj Still another need arises whereit is necessary ito suspend equipment in the tom h'ole chokes.

well conduit such astestinglinstruinentsgstorin chokes or bot- 1,;

Certain e! i ra t, l99l ml1 9YPlhFQ pertai -t t r ou's functions described above have .relatiyely large-vex subject'to bein g unintentionaily lodged in de "becomelodged'and aseries' of'shea'r pins is also provided in a the tmovable'cornponentls of the tool to even further ensure v i h i against accidentalsetting. r i

dimensions or require friction drags withzthe:.r.es lllt that freemovement through the ;well co'nduit'is limit'ed'and the toolsare;

stricted sections of'the concinit If such lodgingld sgoce r, the; 1

anchoring: mechanisms tis'nally employed in snchxtool conduit. In certain of theprior art designs,; the-'anchoring mechanism may be accidentallyactivated whil it is being' moved through the conduitjevenin the absence o'f anyactual lodging of the tool. If the tool design does -not pe rmit it to be released and retrieved when improperly anchored, a costly;

fishing or milling job must be performed-to remove the tool r from the well conduit. The nonretrievabietoolsare also'relatively expensive withrespect-to retrievable typesjn that-they be reused any number of times.

may be'employed only oncewhereas theret'riev abletool may, ;40

' Fl G."-;1 is a longitndinalcrosssection,partially developed in The anchorin mecha isms em lo 'edin riorart tools ma t ,y r r I v g I! M Phys P elevat on;nllustrating also cause tronbleif, after having-been positioned'at the desired subsurface loc ation, they failto prop erly anchor'the 5.

In other respects, where accejs's-through the tool is required,: Q

anchoring means have"heenfullylset the internaldimensions of the tool shouldbej 'asflarg decreased andithe external dimensions arelihcreaised resulting in a limited access'ivay -through.th'etool andiagreater ten' fl fl,

mandrel which extend throng etpr seit srem o a rs ud anchoredat a subsn'rf: el locationfwithinlagwell lgore by suitable Setting tool which is preferahiyoperableby wire line techniques. The external dimensions of the tool are relativelyl small with respect to the internal diameter of the wellconduit; i

fected by simply closing the mandrel passage with a suitable shoe. By properly-spacing;the-packers, the tool may be employed as a straddle pack-off-vto isolate a zone within the well conduit with comrn unication being maintained through the zone bymeans of the central passage in'the mandrel.

The packers and slips of the tool-in any of its forms may be set inthe well conduit without jarring action or friction drags,

positive setting action isrequired to anchor thetool in the well conduit to prevent inadvertent setting of the tool should it Subsequent recovery of the set tool is effected by lowering a esuitableovershot aboutailip formed on the locking means and l a h v v v a I I; preventft he tool frombeing-blown upholeby differential presrnadvertently activated during attemptstofreeatheitoo Y the result that the tools are even moresecurelylockedinthei' sure. 1

if The'working components of the tool are few, which reduces the possibility of malfunctiomand they-are also relatively inexpensive to :constru ct and assemble 'The tool may be BRIEF DESCRIPTION OF THE DRAWINGS ithe presentinvention in the form of a bridge plug; and i FIGLZ is a partial longitudinal section, partially developed elevation; illustrating the present invention in the form of a straddle-pack otf.

DESCRlPTlON OF THE PREFERRED EMBODIMENTS I Structure of the Tools With reference-toFIGQ- lithe tool 10 of the present inven- I 7 tion employs a tubular. central ,mandrelrll formed in two threadedly;,engagedsections 1 1a andl lb locked together by a set screwil 1c. The mandrel 11 extends through an outer body which includes an elastonie'ric packerlZ, metallic slips 13, a

conyexlyrtapered conical spreaderM and a releasable locking mechanismlS. The lower end of the mandrel section 11b is threadedlyengaged with a shoe 16 which acts as a lower bearing surface forthe packer 12 and seals a central passage 11d 'e'x'tending throughthe mandrel llr The shoe 16 is provided witha concave end surfacew'hich receives the convex end surfacello f the pa'ckeri 12:to contain the packeras it is comv pressedi A n O-ringllfia ofrubber or'other-suitable material is .65

disposed between the shoe 16 and the mandrel 11 to provide a 3 leak-proof seal of the mandrel passage lid. The shoe 16 is to prevent lodgin g or premature setting of the tool ii'rthe well.

conduit and the internaldime'nsions-of the center rnandrelare more packers mayibe employed with the central pas'sage held insecure engagement with the mandrel section 11b by means of a set screw 16b which extendsradially through the side ofthe shoe 16 and bears against the mandrel.

' relatively largetopermit ready ac css through-theme] whe i 1 The slips 13 include an enlarged tubular base 13a which is has been set. I i l The tool is extremely versatileinthat itmaybeeasily converted to'act as either-an inside tubing packfofflstraddle pac 1. off or as a bridge plug. When employedias'a pack -oflf one' orprovided at its lower-axial end with a concave bearing surface adapted-toreceive andcontain a'convexly tapered surface at the upper end ofthe packet; 12. A series of resilient metal fingers 13b extend upwardly from the base to form the body 'of-the slips 13. The upper end portion of each of the fingers 13b includes an enlarged wedge-shaped body having laterally developed teeth 130 formed on its external surface. The under surfaces 13d of the wedge-shaped bodies are outwardly tapered and extend over a conical external surface 140 on the cone spreader 14.

The locking mechanism 15 includes a closed tubular body portion 15a which closely encircles the mandrel section 11a. Locking fingers 15b extend downwardly from the body portion of the locking mechanism and terminate in wedge-shaped bodies having lateral teeth 15c formed on their under surfaces and outwardly tapered faces 15d formed on their external surfaces. The teeth 15c interlock between lateral teeth lle formed on the external surface of the mandrel section 11a, and the tapered faces 15d bear against a concave surface 14b formed internally of the cone 14. The upward axial movement of the locking mechanism 15 is confined by means of a collar 17 which encircles the fingers 15b and is threadedly engaged with the cone 14. The upper axial end surface of the collar 17 also acts as a bearing surface for a tubular setting sleeve S forming a portion of a setting mechanism S. As will hereinafter be more fully explained, an internally developed constriction S in the setting sleeve S limits the upward movement of the locking mechanism 15 during the setting procedure and a radially extending tapered lip 15c-formed on the locking body 150 is employed for retrieving the tool after it has been set in the well conduit and released from the setting mechanism S.

With reference to both of the FIGS, the tool 10, or the modified tool 110 as the case may be, is set in a well conduit C by means of the setting mechanism S which moves the mandrel 11 upwardly with respect to the components of the outer body of the tool 10. While any suitable means may be employed for setting and retrieving the tool 10, the mechanism described in US. Pat. application Ser. No. 764,763 filed Oct. 3, I968, entitled Electric Setting Mechanism for Subsurface Well Tools and invented by the present applicant is particularly well suited for this purpose.

Two shear pins 18 and 19 extend through the cone 14 and slips 13 and into the mandrel sections 11a and 11b respectively to prevent relative movement between the pinned components before such time as the tool 10 is to be set. A third shear pin 20 is provided for securing a movable rod S from the setting mechanism S to a centrally apertured connecter fitting 21 which is threadedly engaged to the top of the mandrel section 11a. The pin 20 is held in position by two set screws 20a and 20b which extend radially through the fitting The modified form 110 of the invention illustrated in FIG. 2 is exactly like that of FIG. 1 except that the shoe 16 has been removed and a packer 112, bearing members 122, spacer 123, mandrel section lllb and open ended shoe 116 have been added. The bearing members 122 are formed with a narrow tubular body 122a slidably disposed under the spacer 123 and an enlarged portion 12211 which is provided with a concave end surface for containing the packers 12 and 112. Complete retraction of the expanded packers 12 and 112 is assisted by radial bores 11f and lllf in the mandrel sections 11b and lllb respectively to prevent fluid from being trapped between the packers and the mandrel. FIG. 2 also illustrates the tool as it appears when it is set in a well conduit C. The setting mechanism S illustrated in FIG. 2 has also been modified by replacing the setting sleeve 5,, with a retrieving sleeve 8., and attaching an overshot locking sleeve S to the movable setting rod 8,. As will hereinafter be more fully explained, the modified form of the setting mechanism is adapted to attach to the tools 10 and 110 and release them from their set condition to permit their retrieval from the well conduit C.

Setting and Release of the Tools The setting of both forms of the invention is similar and may be described with initial reference to the bridge plug ofFIG. 1. When the desired subsurface location within the well conduit C has been reached, the setting mechanism S is energized and the rod S and attached mandrel 11 are drawn upwardly through the stationary setting sleeve S This motion positions the iower end of the sleeve S, against the upper axial end of the collar 17 and prevents upward movement of the cone l4. Continued upward'movement of the mandrel l1 severs the shear pin 18 and draws the slips l3 upwardly with respect to the stationary cone 14 causing the wedge-shaped end portions of the slip fingers 13b to expand radially outwardly as the internal slip surfaces 13d advance along the cone surface 14a. The engagement of the locking mechanism teeth 15c and mandrel teeth 11a draws the locking mechanism 15 upwardly during this initial movement of the mandrel until the upper end of the mechanism 15 engages the internal shoulder 8,, in the setting sleeve 8 With the mechanism 15 thus raised within the cone 14, the locking mechanism teeth 15c are forced outwardly by the movement of the mandrel teeth lle which permits the mandrel to continueto move freely in an upward direction. With continued upward movement of the mandrel 11, the slip fingers 13b continue to open radially as they move along the cone surface 140 until they wedge tightly between the cone 14 and the internal wall of the conduit C in the manner illustrated in FIG. 2. Further upward movement of the slips 13 is thereafter prevented and the continued upward motion of the mandrel 11 severs the second shear pin 19 which permits the mandrel to continue to move upwardly through the slips 13. Once the slips become stationary, subsequent upward movement of the mandrel 11 compresses the packer 12 between the bearing surfaces of the moving shoe 16 and the stationary base 13a of the slips 13. As the packer 12 is thus foreshortened axially, it expands radially until it engages and bears tightly against the inner wall of the well conduit C.

When the lifting force exerted by the setting bar S exceeds a preestablished maximum value, the third shear pin 21 is severed and the mandrel 11 is released from the setting tool S and immediately begins to move downwardly under the restorative influence of the compressed packer 12. The locking teeth 150 are resiliently engaged against the mandrel teeth lle and the initial downward movement of the mandrel draws the locking mechanism 15 downwardly and wedges the lower ends of the fingers 15b between the mandrel and the internal cone surface 14b. Radial opening of the fingers 15b is prevented in this position and, as illustrated in FIG. 2, the teeth 15c and teeth lle securely lock to prevent further downward movement of the mandrel 11 which locks the tool in its set condition within the well conduit C.

Retrieval of the tools 10 or is effected by modifying the setting mechanism S as illustrated in FIG. 2 and lowering it over the top of the anchored tool. With reference to FIG. 2, sleeve S, is provided with a plurality of downwardly extending fingers, each of which includes a tapered surface S and an internal shoulder S The setting mechanism S is lowered over the top of the tool 110 with the retrieving sleeve 8,, raised axially above the fingers of the overshot sleeve S to permit radial expansion of the fingers. The upper surface of the connecter fitting 21 is tapered to assist in guiding the sleeve S past the fitting as the setting mechanism is lowered. When the tapered surface 8,. engages the taper at the upper end of the locking mechanism 15, the fingersof the sleeve S, are forced radially outwardly and continued lowering of the mechanism S allows the fingers to snap over the lip 15e into the position illustrated in FIG. 2.

With the sleeve 5,, thus positioned, the setting mechanism is energized to pull the rod 5,, upwardly with respect to the retrieving sleeve 8, This movement initially draws the lower end of the sleeve 8,, into engagement with collar 17 and subsequently exerts a lifting force on the locking mechanism 15. The presence of the sleeve 8,, about the fingers of the overshot sleeve 5,, prevents the fingers from opening radially and the upward force on the locking mechanism 15 raises the mandrel 11 through the cone 14 until the locking mechanism fingers 15b are free to open radially which releases the mandrel 11. The axial forces exerted by the compressed packers 12 and 112 then move the mandrel downwardly through the cone 14 J and slips 13 which permits the packers to return to their lifting of the cone 14 permits the resilient fingers 13b of the slips to retract radially inwardly which completely releases the tool from the well conduit C. The tool 110, or as the case may be, when thus freed from the well conduit C may then be drawn upwardly with the setting mechanism S to the well surface.

It will be understood that any number of packers may be employed with the tools of the present invention and that the spacing between packers may be any desired length. Similarly, the lower. ends of the mandrels may be plugged or unplugged and any desired equipment may be suspended therefrom.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated constructionmay be made within the scope of the appended claims without departing from the spirit of the invention.

lclaim:

1. A tool of the type which may be anchored in a well conduit by a setting mechanism comprising:

a. a tool body having first and second axially spaced ends;

b. connection means for securing said body to the setting mechanism;

c. anchoring means included between said first and second body ends for mechanically anchoring said body to the surrounding wall of the conduit;

d. sealing means included between said first and second body ends for forming a seal between saidbody and the conduit;

e.- setting means included in said body and operable by the setting mechanism for sequentially moving first said anchoring means and then said sealing means into engagement with the conduit; f. first releasable means included in said connection means for releasing said body from the setting mechanism after said anchoring means and said sealing means are engaged with the conduit; and locking means for retaining said anchoring means and said sealingmeans in engagement with the well conduit after said body is released fromthe setting mechanism.

2. The tool as defined inclaim 1 further including retrieving means for releasing said locking means and moving said anchoring means and said sealing means out of engagement with the well conduit. I

3. The tool as defined inclaim 1 further including:

a. a mandrel having first and second axially spaced ends extending inter'nallyof said anchoring means and said sealing means; and

b. a passage included in said mandrel extending axially between said first and second mandrel ends.

4. The tool as defined in claim 2 further including:

a. a mandrel having first and second axially spaced ends extending internally of said anchoring means and said sealing means; and g b. a passage included in said mandrel extending axially between said first and second mandrel ends.

5. The tool as defined in claim 1 wherein said anchoring means includes:

a. a plurality of radially movable friction members; and

b. a spreader means having a convex external surface for moving said friction members radially into engagement ,with the'well conduit.

6. The tool as defined in claim 1 wherein said sealing means includes at least one radially expandable elastomeric packer.

7. The tool as defined in claim 2 wherein said anchoring means includes:

a. a plurality of radially movable friction members; and b. a spreader means having a convex external surface for moving said friction members radiallyinto engagement with the well conduit. 5 8. The tool as defined in claim 3 wherein said anchoring means includes:

a. a plurality of radially movable friction members; and b. a spreader means having a convex external surface for moving said friction members radially into engagement with the well conduit. 9. The tool as defined in claim 4 wherein said anchoring means includes:

a. a plurality of radially movable friction members; and b. a spreader means having a convex external surface for moving said friction members radially into engagement with the well conduit. 10. The tool as defined in claim 9 wherein said sealing means includes at least one radially expandable elastomeric acker. 2 11. The tool as defined in claim 8 wherein said locking means includes: v

a. a concave internal surface formed on said spreader means;

b. wedge members disposed between said mandrel and said concave surface; and

c. cooperating locking means formed on said mandrel and said wedge members for preventing axial motion of said mandrel in one direction when said cooperating locking means are interlocked.

12. The tool as defined in claim 11 wherein said retrieving means include means operable by the setting mechanism for releasing said cooperating locking means to permit said mandrel to move in either axial direction.

13. The tool as defined in claim 12 including outlet mean's forming an escape passage for fluids and gasses trapped behind said packer to permit said packer to fully disengage the conduit wall.

14. The tool as defined in claim 9 wherein said mandrel is movable relative to said spreader means, friction members and sealing means for moving said friction members and said sealing means both into and out of engagement with the conduit.

'15. The tool as defined in claim 9 wherein said setting means includes: y

a. second releasable connection means securing said spreader means and said mandrel against relative axial movement; and

b. third releasable connection means securing said friction members andsaid mandrel against relative movement.

16. The tool as defined in claim 15 wherein said first, second and third releasable connection means include shear pins.

17. The tool as defined in claim 1 including a plurality of axially spaced sealing means disposed between said first and second body ends for sealing a zone within the well conduit.

18. The tool as defined in claim 16 further including means for sealing said mandrel passage.

19. The tool as defined in claim 16 further including a plurality of axially spaced sealing means disposed between said first and second body ends for sealing a zone within the well conduit- 20. The tool as defined in claim 18 further including a plurality of axially spaced sealing means disposed between said first and second body ends for sealing a zone within the well conduit.

21. A retrievable oil tool for subsurface use in a well conduit comprising:

a. a central mandrel having first and second axially spaced d. sealing means carried externally of said mandrel between said first and second mandrel ends for forming a seal between said mandrel and the conduit; and

e. locking means disposed about said mandrel for securing said mandrel against axial movement in one direction relative to said anchoring means and sealing means with said locking means including retrieving means selectively movable axially with respect to said mandrel for releasing said mandrel to permit mandrel movement in both axial directions relative to said anchoring means and said sealing means.

22. The tool as defined in claim 21 wherein said anchoring means includes:

a. a plurality of radially movable friction members circumferentially disposed externally about said mandrel; and

b. an axially movable spreader means encircling said mandrel and including a convex external surface for moving said friction members radially into engagement with the well conduit as said spreader means moves axially with respect to said mandrel.

23. The tool as defined in claim 22 wherein said locking means includes:

a. a concave internal surface included with said spreader means;

b. wedge membersdisposed between said mandrel and said concave surface; and

c. cooperating locking means formed on said mandrel and said wedge members for preventing axial motion of said mandrel in one direction when said cooperating locking means are interlocked.

24. The tool as defined in claim 23 wherein said retrieving means includes release means operable by a setting mechanism for releasing said cooperating locking means to permit said mandrel to move in either axial direction.

25. The tool as defined in claim 23 further including:

a. second releasable connection means securing said spreader means and said mandrel against relative axial movement; and

b. third releasable connection means securing said friction members and said mandrel against relative movement.

26. The tool as defined in claim 25 wherein said first, second and third releasable connection means include sequentially severable shear pins for sequentially anchoring said friction means, and sealing means and releasing said mandrel from the setting mechanism.

27. The tool as defined in claim 25 further including a plurality of axially spaced sealing means disposed between said first and second body ends for sealing a zone within the well conduit.

28. The tool as defined in claim 26 wherein said mandrel further includes a central passage extending axially along at least a portion of its length.

29. The tool as defined in claim 28 further including outlet means forming an escape passage for fluids and gases trapped behind said packer to permit said packer to fully disengage the conduit wall.

30. The tool as defined in claim 1 wherein:

a. said anchoring means further includes radially movable friction members and a spreader means disposed about a mandrel for radially moving said friction members into engagement with the well conduit; and

b. said locking means includes wedge means disposed between said spreader means and said mandrel for selectively preventing axial movement of said mandrel through said spreader means.

31. The tool as defined in claim 1 wherein:

a. said anchoring means further includes a plurality of radially movable friction members and a spreader means disposed about a mandrel for moving said friction members radially into engagement with the well conduit; and

b. said mandrel is movable axially relative to said spreader means for moving said friction members and said sealing means into engagement with the conduit.

32. The tool as defined in claim 1 further including: a. first and second compression members axially movable relative to each other for compressing said sealing means to move said sealing means radially outwardly away from said body; and

b. connecting means connecting said anchoring means and said first compression member for preventing relative axial movement between said anchoring means and said first compression member.

33. The tool as defined in claim 22 wherein:

a. said lock means includes a tubular lock base means circumferentially disposed about said mandrel, a plurality of fingers extending axially from said lock base means, wedge means secured to said fingers, said wedge means disposed between said spreader means and said mandrel and a plurality of circumferentially extending grooves formed along the internal surface of said wedge means for selectively engaging a plurality of circumferentially extending extending grooves formed along the external surface of said mandrel;

b. said anchoring means-includes a tubular anchor base means circumferentially disposed about said mandrel and secured to said plurality of radially movable friction members whereby said anchor base and said friction members are axially fixed with respect to each other; and

c. said sealing means includes at least one radially expandable elastomeric packer positioned between plural, axially spaced compressive members with one of said compressive members being axially fixed relative to said anchor base and another compressive member being secured to and axially fixed with said mandrel whereby axial movement of said two compressive members toward each other axially foreshortens and radially expands said packer. 

